1. Field
An exemplary embodiment relates to a light emitting device.
2. Description of the Related Art
A light emitting device is a self-emitting device including a light emitting layer between two electrodes. The light emitting device may be classified into an inorganic light emitting device and an organic light emitting device depending on a material of the light emitting layer.
The organic light emitting device forms an exciton, which is a hole-electron pair, by combining holes received from an anode electrode and electrons received from a cathode electrode inside an organic light emitting layer, and emits light by energy generated when the exciton returns from an excited state to a ground state.
The organic light emitting device may be classified into a passive matrix type organic light emitting device and an active matrix type organic light emitting device depending on a driving manner.
The active matrix organic light emitting device has a low power consumption and small crosstalk between pixels as compared with the passive matrix organic light emitting device, and thus can be suitable for a large-sized display device or a high-definition display device. The active matrix organic light emitting device generally includes at least one subpixel at each of intersections of N scan lines and M data lines that are arranged in a matrix format on a substrate. The subpixel includes at least one thin film transistor, a capacitor, and an organic light emitting diode.
The thin film transistor includes a source electrode, a drain electrode, and a gate electrode. The organic light emitting diode is electrically connected to the source electrode or the drain electrode of the thin film transistor. The thin film transistor may be classified into a switching thin film transistor and a driving thin film transistor. The switching thin film transistor or the driving thin film transistor may include a compensation circuit depending on their properties.
In the organic light emitting device, when the switching thin film transistor is turned on by a scan signal supplied through the scan line, the capacitor stores a data signal supplied through the data line a data voltage form. The data voltage stored in the capacitor turns on a gate of the driving thin film transistor, and thus the organic light emitting diode can emit light.
The organic light emitting device includes an aging pad at an edge of a driving device that is positioned on the substrate to supply the data signal and the scan signal, and performs an aging process using the aging pad. However, the related art aging pad has a structural demerit (for example, a reduction or a drop in a current due to a resistance, i.e., IR drop) that cannot uniformly perform the aging process.